1. Field of the Invention
The invention relates to treating hollow anatomical structures having a lumen. More specifically, the invention relates to treating one or more diseased body lumens, creating anastomoses between such hollow body structures, and using magnetism to secure anastomotic components to such structures, for example, in conjunction with creating an anastomosis.
2. Description of Related Art
Despite the considerable advances that have been realized in both interventional cardiology and cardiovascular surgery, heart disease remains the leading cause of death throughout much of the world. Coronary artery disease, or arteriosclerosis, is the single leading cause of death in the United States today. As a result, those in the cardiovascular field continue to search for new treatments and improvements to existing treatments.
Coronary artery disease is currently treated by interventional procedures such as percutaneous transluminal coronary angioplasty (PTCA), coronary stenting and atherectomy, as well as surgical procedures including coronary artery bypass grafting (CABG). The goal of these procedures is to reestablish or improve blood flow through occluded (or partially occluded) coronary arteries, and is accomplished, for example, by enlarging the blood flow lumen of the artery or forming a bypass that allows blood to circumvent the occlusion. What procedure(s) is used typically depends on the severity and location of the blockage. When successful, these procedures restore blood flow to myocardial tissue that had not been sufficiently perfused due to the occlusion.
Another proposed treatment places the target vessel, e.g., a coronary artery, in direct fluid communication with a heart chamber containing blood, for example, the left ventricle. Blood flows from the ventricle into a conduit that is in fluid communication with the artery; as such, this treatment may be described as a ventricular bypass procedure. Benefits of this procedure include obviating the need to manipulate the aorta, for example, as is done when a side-biting clamp is used in a typical CABG procedure to create a proximal anastomosis between the bypass graft and the aorta. Clamping or otherwise manipulating the aorta places the patient at risk in some cases due to the likelihood that such manipulation will release embolic material into the bloodstream. Some challenges associated with this procedure include delivering and deploying the conduit in the patient's body in proper position with respect to the heart chamber and the coronary vessel.
A particularly challenging task that must be performed during many of these and other revascularization procedures is suturing one hollow structure to another hollow structure. For instance, one end of a graft vessel is sutured to a source of blood, such as the aorta, a heart chamber or another blood vessel, while another end of the graft vessel is sutured to a target vessel, such as a coronary artery having an occluded lumen. The small diameter of the hollow structures involved, typically from 1 mm to 4 mm, makes forming a handsewn anastomosis a highly technical and time-consuming procedure. The difficulty in forming the sutured anastomosis is exacerbated when access to the target vessel is restricted or limited, as in a minimally invasive or percutaneous procedure. This problem can also arise in non-cardiovascular applications that utilize handsewn anastomoses, for example, treating peripheral vascular disease or injury, creating AV (arteriovenous) shunts, etc.
While those in the art have proposed various anastomotic coupling, none has performed well enough to receive any significant level of acceptance in the field. Many of the proposed couplings penetrate or damage the wall of the hollow structures, do not remain patent, fail to produce a fluid-tight seal between the conduit and vessel, or are simply too cumbersome and difficult to deliver or deploy.
It should be noted, though, that a more recently proposed technology which uses magnetism to treat hollow anatomical structures has enjoyed clinical success in creating an anastomosis between a graft blood vessel and a coronary artery. This anastomotic technology, which was developed by Ventrica, Inc., of Fremont, Calif., and is referred to as the MVP™ (Magnetic Vascular Positioner) anastomotic system, provides considerable benefits over other proposed technologies. Nevertheless, there remains room in the art for improvement with respect to a number of technological and procedural areas.
For example, it is desirable to maximize the ability of the technology to be used in a minimally invasive manner, such as in a procedure performed by a robotic system. As another example, it is desirable to minimize the amount of foreign material in the blood flow path so as to decrease the chance of thrombosis. Achieving this goal, however, must be balanced with the need to form a secure connection between the anastomotic components, or between a component and a hollow body structure.